class Solution:
    def countGoodStrings(self, low: int, high: int, zero: int, one: int) -> int:
        dp = [0]*100010
        ans = 0
        mod = int(1e9) + 7
        dp[0] = 1
        for i in range(1,high + 1):
            if i - zero >= 0:
                dp[i] += dp[i - zero]%mod
            if i - one >= 0:
                dp[i] += dp[i - one]%mod
            dp[i] %= mod
            if i>= low:
                ans += dp[i]
                ans %= mod
        return ans

